McDonald’s Japan has launched a peculiar contest that involves customers photo- searching for clues left by a yellow-suited “Nugget Thief” at stores around the country. The prize? A non-edible McNugget made of 18-karat gold, weighing about 1.8 ounces.

The new campaign, Rocket News 24 reports, comes as the fast food chain steps up efforts to attract customers across the Asian country.

In February, McDonald’s Japan posted its first profit in three years. In 2015, however, it reported a loss of 34.7 billion yen, or over $300 million.

The hunt for the mysterious nugget thief is set to run from June 8 to June 28, and during that time one person per day will also win 39 days of chicken nuggets.